What are sintered Brass and Bronze silencers?

Sintered brass and bronze silencer, Pneumatic silencers, also called mufflers, safely and quietly vent pressurized air to atmosphere. They are commonly installed on air valves, cylinders, manifolds and fittings. Without a muffler, air exhausting from many types of pneumatic-powered equipment can be so loud as to be detrimental to the surrounding environment and potentially harm workers. Noise results when fast-moving, turbulent air exiting a port collides with the surrounding static air. Unsilenced pneumatic exhaust can be considered an air jet. In most industrial setting airflow exits at a constant velocity through an orifice and generates noise, related to the choking effect of the port and velocity. Acoustic power (noise) is a product of factors like air density and turbulence and, especially, velocity, which has an exponential effect (≈ V⁶) on noise generation. And above about 25 psi (2 bar), reducing pressure has minimal effect on noise abatement.

Use of brass and bronze silencers:

Thus, mufflers are usually needed. Typically, the devices are installed directly at the exhaust port and diffuse the released air through a porous material that increases the surface area which, in turn, reduces velocity, turbulence and noise levels. These silencers can reduce the noise from pneumatic equipment by 15 to 35 dB[A] compared to an unmuffled outlet. This is significant. Keep in mind that a 10 dB(A) reduction equates to cutting the sound level in half. Mufflers can be constructed of plastic or metals like brass and stainless steel. They come in differing versions depending on the application. Common design styles include cone, flat-face and cylindrical shapes. Plastic units usually have injected-molded bodies with plastic fibers or sintered plastic or metal powder inside as the noise-reducing medium. They tend to be economical, lightweight and offer high chemical resistance, and often better noise reduction than same-size metal products. General-purpose brass products often have machined metal bodies with sintered bronze powder or compacted metal wool as the silencing material. They generally handle temperatures to about 300° F.